14 



BULLETIN 240, U. S. DEPAETMENT OF AGEICTTLTTJEE. 



in order to eliminate this factor of possible infection. The result of 

 these experiments are shown in Table 3. 



Table 



-Comparison of bacterial reductions in milk pasteurized in steamed 

 bottles and in pasteurized milk bottled while hot. 





Raw milk. 



Milk pasteurized at 145° F. for 30 minutes. 



Sample No. 



Hot pasteurized milk in 

 hot steamed bottles. 



Milk pasteurized in 



steamed bottles. 1 





Bacteria 

 per c. c. 



Bacteria 

 per e.c. 



Percentage 

 reduction. 



Bacteria 

 perc.c. 



Percentage 

 reduction. 



24 



24,900 



94, 000 



305,000 



235,000 



176, 000 



97,000 



230, 000 



124, 000 



450,000 



' 3, 950, 000 



985,000 



190, 000 



380 



860 



21,800 



5,400 



2,200 



5,900 



6,300 



920 



4,200 



4,320 



11, 800 



7,500 



98.47 

 99.08 

 92.85 

 97.70 

 98.75 

 93.91 

 97.26 

 99.26 

 97.47 

 99.89 

 98.80 

 96.06 



570 

 2,200 



55, 800 

 7,600 



11,400 

 8,350 

 5,500 

 1,500 



11, 400 

 3,520 



18,400 

 9,300 



97.71 



25 



97.66 



26 



81.70 



27 



96.76 



28 



93.52 



29 



30 



31 



32 



33 



91.39 

 97.61 

 98.79 

 97.46 

 99.91 



34 



98.13 



35 



95.10 









571,766 



5,965 



97.46 



11,295 



95. 4S 







1 Bottles were steamed two minutes, and cooled before they were filled with raw milk. 



It will be seen that the results again were in favor of the milk 

 pasteurized in bulk and bottled while hot. Of the 12 samples in the 

 experiment 10 showed lower counts than when the milk was pasteur- 

 ized in the bottles. 



The average count of the raw milk was 571,766 bacteria per cubic 

 centimeter. After pasteurization in bulk, followed by bottling hot, 

 the count was 5,965, and a portion of the same milk pasteurized in 

 bottles averaged 11,295 bacteria per cubic centimeter. In several of 

 the samples the count in the milk pasteurized in bottles was very 

 much higher than in the same milk pasteurized in bulk and bottled 

 hot. The explanation of these marked differences is not known. 

 While minor differences are always within the limits of the errors 

 of bacteriological methods, the great differences found in many cases 

 can not be explained in this manner. 



PREVENTION OF BOTTLE INFECTION BY BOTTLING HOT MILK AND 

 BY PASTEURIZATION IN BOTTLES. 



Since the process of pasteurizing milk in bulk and bottling -while 

 hot enables the use of hot. steamed bottles which can be directly 

 fdled with hot milk, it should be expected that there would be no 

 contamination added to the milk during bottling. 



To determine this point eight samples of milk were pasteurized 

 in bulk and bottled hot in hot. steamed bottles. The bacteriological 

 results are shown in Table 4. column A. Two steamed and cooled 



